A first principles study on transport properties of benzene-based molecular junctions: The effect of side groups and anchoring atoms

Using density functional theory in conjunction with the nonequilibrium Green's function technique, the electron transport through the substituted benzenedithiol molecules inserted between two gold electrodes was investigated. We calculated the current–voltage characteristics for positive and negative bias voltages. It was found that due to interaction with the applied electric field, the current–voltage curve of amino substituted benzene molecule is asymmetric and exhibited switching behavior. Despite the asymmetric structure of benzene molecule substituted with hydroxyl group, there was no obvious rectification behavior in its current–voltage curve, but a peak and a valley were observed in its current–voltage characteristics. Furthermore, we calculated the current–voltage curve for benzenediselenol and found that the best anchoring atom depends on bias voltage.

Research highlights
► Due to interaction with the applied electric field, the current–voltage curve of amino substituted benzene molecule is asymmetric.
► Current–voltage curve of amino substituted benzene molecule exhibited switching behavior.
► Despite the asymmetric structure of benzene molecule substituted with hydroxyl group, there was no obvious rectification behavior in its current–voltage curve, but a peak and a valley were observed in its current–voltage characteristics.